Cellulose-Based Adsorbents for Heavy Metal Removal

Pollution of water bodies has become a worldwide problem since the last few decades due to the increased load of population and industrial activities. Excessive use of fertilizers and pesticides is also an important reason. Heavy metals are one of the key toxic elements of wastewater and remain for a long time in the system due to their nonbiodegradability. Adsorption technique using activated carbon is a convectional approach for heavy metal eradication but a costly method. Scientists are attempting various waste materials in modern days to avoid the expensive activated carbon. Cellulose is a widely available, cheap natural polymeric material and has metal binding properties. Researchers have attempted several natural cellulose-based materials and found promising results for heavy metal removal and further observed that the adsorption capacity enhances with its treatment. This chapter highlights a detailed review of works carried out by scientists using the cellulosic materials from different natural sources for heavy metal remediation. Modification of cellulosic materials either through physical and chemical processes or by grafting enhances their performance, strength, and reusability. The char and activated carbon prepared from cheap cellulosic sources may even replace the costly commercial activated carbon. The performances of modified cellulose, cellulose beads, grafted cellulose, cellulosic composites, nano-cellulose, and hydrogels on heavy metal eradication have been elaborated. A broad list of different cellulose-based adsorbents and their adsorption capacities has been compiled, which indicates their significant comparable metal removal capacities with the commercial adsorbents. Moreover, most of the modified adsorbents have strong regeneration ability and are reusable in many cycles efficiently with a feasibility of metal recovery.